The Tapping Finger Identification (TFI) technology disclosed in US patent application, US20060190836A1, by Su et al., presents alternative means to data entry on conventional keyboards. TFI-enabled keyboards determine user input not only based on which key was pressed, but also on which of the user's finger was used to press the key, as each key may be capable of selecting multiple symbols or functions.
The use of visual or audible cues to improve the accuracy and ease of use of data entry interfaces has been proposed for some systems. This is especially important for virtual keyboards, such as those keyboard systems proposed in U.S. Pat. No. 5,767,842 (Korth) and U.S. Pat. No. 7,151,530 (Rafii). These include: displaying key layout on-screen, indicating hand status on-screen, and using audible sound to indicate key press events.
However, all these solutions are designed for traditional keyboard systems in which the various tapping fingers are not considered or differentiated in such designs. In TFI, it is important to not only indicate by visual and/or audible cues what keys are pressed, but also which fingers are being (or about to be) used in actuating keys.